Javascript to add a tool-bar button?

[JimTM]

I wish to copy selected text from a pdf to an editor program, in this case Emacs.
I understand that this can be done in Adobe reader by using this javascript:
app.addMenuItem({cName:"org-capture", cParent:"Tools", cExec:"app.launchURL('org-protocol://capture://' + encodeURIComponent(this.URL) + '/' + encodeURIComponent(this.info.Title) + '/');"}); I assumed that placing this script in a js file in the foxit js sub-directory would work. But no.

Is it possible to do this in Foxit using javascript?

Thanks
Jim